Medicine and Health Sciences Commons^™

Trajectories Of Symbolic And Nonsymbolic Magnitude Processing In The First Year Of Formal Schooling, Anna A. Matejko, Daniel Ansari

Brain and Mind Institute Researchers' Publications

Sensitivity to numerical magnitudes is thought to provide a foundation for higher-level mathematical skills such as calculation. It is still unclear how symbolic (e.g. Arabic digits) and nonsymbolic (e.g. Dots) magnitude systems develop and how the two formats relate to one another. Some theories propose that children learn the meaning of symbolic numbers by scaffolding them onto a pre-existing nonsymbolic system (Approximate Number System). Others suggest that symbolic and nonsymbolic magnitudes have distinct and non-overlapping representations. In the present study, we examine the developmental trajectories of symbolic and nonsymbolic magnitude processing skills and how they relate to each other in …

In Vivo Mri Signatures Of Hippocampal Subfield Pathology In Intractable Epilepsy., Maged Goubran, Boris C Bernhardt, Diego Cantor-Rivera, Jonathan C Lau, Charlotte Blinston, Robert R Hammond, Sandrine De Ribaupierre, Jorge G Burneo, Seyed M Mirsattari, David A Steven, Andrew G Parrent, Andrea Bernasconi, Neda Bernasconi, Terry M Peters, Ali R Khan

Brain and Mind Institute Researchers' Publications

OBJECTIVES: Our aim is to assess the subfield-specific histopathological correlates of hippocampal volume and intensity changes (T1, T2) as well as diff!usion MRI markers in TLE, and investigate the efficacy of quantitative MRI measures in predicting histopathology in vivo.

EXPERIMENTAL DESIGN: We correlated in vivo volumetry, T2 signal, quantitative T1 mapping, as well as diffusion MRI parameters with histological features of hippocampal sclerosis in a subfield-specific manner. We made use of on an advanced co-registration pipeline that provided a seamless integration of preoperative 3 T MRI with postoperative histopathological data, on which metrics of cell loss and gliosis were quantitatively …

Reaming Does Not Affect Functional Outcomes After Open And Closed Tibial Shaft Fractures: The Results Of A Randomized Controlled Trial, Carol A. Lin, Marc Swiontkowski, Mohit Bhandari, Stephen D. Walter, Emil H. Schemitsch, David Sanders, Paul Tornetta

Bone and Joint Institute

© Copyright 2015 Wolters Kluwer Health, Inc. All rights reserved. Objectives: We sought to determine the effect of reaming on 1-year 36-item short-form general health survey (SF-36) and short musculoskeletal function assessment (SMFA) scores from the Study to Prospectively Evaluate Reamed Intramedullary Nails in patients with Tibial Fractures. Design: Prospective randomized controlled trial.1319 patients were randomized to reamed or unreamed nails. Fractures were categorized as open or closed. Setting: Twenty-nine academic and community health centers across the US, Canada, and the Netherlands. Patients/Participants: One thousand three hundred and nineteen skeletally mature patients with closed and open diaphyseal tibia fractures. Intervention: …

The Expanding Phenotype Of Melas Caused By The M.3291t > C Mutation In The Mt-Tl1 Gene, E. Keilland, C. A. Rupar, Asuri N. Prasad, K. Y. Tay, A. Downie, C. Prasad

Bone and Joint Institute

Crown Copyright © 2016 Published by Elsevier Inc. m.3291T > C mutation in the MT-TL1 gene has been infrequently encountered in association with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS), however remains poorly characterized from a clinical perspective. In the following report we describe in detail the phenotypic features, long term follow up (> 7 years) and management in a Caucasian family with MELAS due to the m.3291T > C mutation and review the literature on m.3291T > C mutation. The clinical phenotype in the proposita included overlapping features of MELAS, MERRF (Myoclonic epilepsy and ragged-red fiber syndrome), MNGIE (Mitochondrial neurogastrointestinal …

Character, Incidence, And Predictors Of Knee Pain And Activity After Infrapatellar Intramedullary Nailing Of An Isolated Tibia Fracture, William Obremskey, Julie Agel, Kristin Archer, Philip To, Paul Tornetta, Mohit Bhandari, Gordon Guyatt, David W. Sanders, Emil H. Schemitsch, Marc Swiontkowski, Stephen Walter, Sheila Sprague, Diane Heels-Ansdell, Lisa Buckingham, Pamela Leece, Helena Viveiros, Tashay Mignott, Natalie Ansell, Natalie Sidorkewicz, Claire Bombardier, Jesse A. Berlin, Michael Bosse, Bruce Browner, Brenda Gillespie, Alan Jones, Peter O'Brien, Rudolf Poolman, Mark D. Macleod, Timothy Carey, Kellie Leitch, Stuart Bailey, Kevin Gurr, Ken Konito

Bone and Joint Institute

© Copyright 2015 Wolters Kluwer Health, Inc. All rights reserved. Objective: To study the activity and incidence of knee pain after sustaining an isolated tibia fracture treated with an infrapatellar intramedullary nail at 1 year. Design: Retrospective review of prospective cohort. Setting: Multicenter Academic and Community hospitals. Patients: Four hundred thirty-seven patients with an isolated tibia fracture completed a 12-month assessment on pain and self-reported activity. Intervention: Infrapatellar intramedullary nail. Outcomes: Demographic information, comorbid conditions, injury characteristics, and surgical technique were recorded. Knee pain was defined on a 1-7 scale with 1 being "no pain" and 7 being a "very …

Differential Effect Of Clomipramine On Habituation And Prepulse Inhibition In Dominant Versus Subordinate Rats., Alvin Yang, Tahira Daya, Karen Carlton, Jin Hui Yan, Susanne Schmid

Brain and Mind Institute Researchers' Publications

Many patients with depression have comorbidities associated with an impairment of sensorimotor gating, such as e.g. schizophrenia, Parkinson Disease, or Alzheimer disease. Anti-depressants like clomipramine that modulate serotonergic or norepinephrinergic neurotransmission have been shown to impact sensorimotor gating, it is therefore important to study potential effects of clomipramine in order to rule out an exacerbation of sensorimotor gating impairment. Prior studies in animals and humans have been inconclusive. Since serotonin and norepinephrine levels are closely related to anxiety and stress levels and therefore to the social status of an animal, we tested the hypothesis that acute and chronic effects of …

The Globalization Of Healthcare: International Agreements & Ontario Academic Health Science Centres, Andrew D. Scarffe

Electronic Thesis and Dissertation Repository

Health systems are beginning to recognize the tremendous opportunity that globalization and international activities present for Academic Health Science Centres. This study explored the nature of international agreements within Ontario Academic Health Science Centres (OAHSC) and presents the exploratory findings to begin to develop an academically defensible body of literature on the topic. This study employed a constructivist grounded theory qualitative methodology, interviewing 14 participants who hold leadership positions within OAHSCs that actively participate in, or interface with, institutions that participate in international agreements (IAs). A conceptual framework is proposed that highlights the: (1) drivers, (2) barriers, (3) international activities, …

Structure And Function Of Gene Regulatory Networks Associated With Worker Sterility In Honeybees., Julia A Sobotka, Mark Daley, Sriram Chandrasekaran, Benjamin D Rubin, Graham J Thompson

Brain and Mind Institute Researchers' Publications

A characteristic of eusocial bees is a reproductive division of labor in which one or a few queens monopolize reproduction, while her worker daughters take on reproductively altruistic roles within the colony. The evolution of worker reproductive altruism involves indirect selection for the coordinated expression of genes that regulate personal reproduction, but evidence for this type of selection remains elusive. In this study, we tested whether genes coexpressed under queen-induced worker sterility show evidence of adaptive organization within a model brain transcriptional regulatory network (TRN). If so, this structured pattern would imply that indirect selection on nonreproductive workers has influenced …

Category Learning In Older Adulthood: A Study Of The Shepard, Hovland, And Jenkins (1961) Tasks., Rahel Rabi, John Paul Minda

Brain and Mind Institute Researchers' Publications

Shepard, Hovland, and Jenkins (1961) examined the categorization abilities of younger adults using tasks involving single-dimensional rule learning, disjunctive rule learning, and family resemblance learning. The current study examined category learning in older adults using this well-known category set. Older adults, like younger adults, found category tasks with a single relevant dimension the easiest to learn. In contrast to younger adults, older adults found complex disjunctive rule-based categories harder to learn than family resemblance based categories. Disjunctive rule-based category learning appeared to be the most difficult for older adults to learn because this category set placed the heaviest demands on …

Pulmonary Ct And Mri Phenotypes That Help Explain Chronic Pulmonary Obstruction Disease Pathophysiology And Outcomes, Eric A Hoffman, David A Lynch, R Graham Barr, Edwin J R Van Beek, Grace Parraga

Medical Biophysics Publications

Pulmonary x-ray computed tomographic (CT) and magnetic resonance imaging (MRI) research and development has been motivated, in part, by the quest to subphenotype common chronic lung diseases such as chronic obstructive pulmonary disease (COPD). For thoracic CT and MRI, the main COPD research tools, disease biomarkers are being validated that go beyond anatomy and structure to include pulmonary functional measurements such as regional ventilation, perfusion, and inflammation. In addition, there has also been a drive to improve spatial and contrast resolution while at the same time reducing or eliminating radiation exposure. Therefore, this review focuses on our evolving understanding of …

Imaging How And Where We Breathe Oxygen: Another Big Short?, Dante P I Capaldi, Fumin Guo, Grace Parraga

Medical Biophysics Publications

The Big Short tells the story of a small group of skeptics who profited from the financial crisis in 2007 by betting against collateralized (mortgage) debt obligations (CDO). Importantly, the novel paints a clear picture of the eccentric nature of contrarians who think divergently and against the grain or bet against an accepted truth or “sure” thing. In a similar manner, Ishii and co-workers’ recent work describes their team’s development of a pulmonary imaging technology that provides divergent and disruptive in vivo lung measurements of oxygen partial pressure in the context of the prevailing and longstanding consensus around FEV1 as …

The Representational-Hierarchical View Of Pattern Separation: Not Just Hippocampus, Not Just Space, Not Just Memory?, B. A. Kent, M. Hvoslef-Eide, L. M. Saksida, T. J. Bussey

Brain and Mind Institute Researchers' Publications

Pattern separation (PS) has been defined as a process of reducing overlap between similar input patterns to minimize interference amongst stored representations. The present article describes this putative PS process from the "representational-hierarchical" perspective (R-H), which uses a hierarchical continuum instead of a cognitive modular processing framework to describe the organization of the ventral visual perirhinal-hippocampal processing stream. Instead of trying to map psychological constructs onto anatomical modules in the brain, the R-H model suggests that the function of brain regions depends upon what representations they contain. We begin by discussing a main principle of the R-H framework, the resolution …

A Rigid Body Model For The Assessment Of Glenohumeral Joint Mechanics: Influence Of Osseous Defects On Range Of Motion And Dislocation, Mark F. Welsh, Ryan T. Willing, Joshua W. Giles, George S. Athwal, James A. Johnson

Bone and Joint Institute

© 2016. The purpose of this study was to employ subject-specific computer models to evaluate the interaction of glenohumeral range-of-motion and Hill-Sachs humeral head bone defect size on engagement and shoulder dislocation. We hypothesized that the rate of engagement would increase as defect size increased, and that greater shoulder ROM would engage smaller defects. Three dimensional computer models of 12 shoulders were created. For each shoulder, additional models were created with simulated Hill-Sachs defects of varying severities (XS=15%, S=22.5%, M=30%, L=37.5%, XL=45% and XXL=52.5% of the humeral head diameter, respectively). Rotational motion simulations without translation were conducted. The simulations ended …

Optimizing The Distribution Of Leg Muscles For Vertical Jumping., Jeremy D Wong, Maarten F Bobbert, Arthur J Van Soest, Paul L Gribble, Dinant A Kistemaker

Brain and Mind Institute Researchers' Publications

A goal of biomechanics and motor control is to understand the design of the human musculoskeletal system. Here we investigated human functional morphology by making predictions about the muscle volume distribution that is optimal for a specific motor task. We examined a well-studied and relatively simple human movement, vertical jumping. We investigated how high a human could jump if muscle volume were optimized for jumping, and determined how the optimal parameters improve performance. We used a four-link inverted pendulum model of human vertical jumping actuated by Hill-type muscles, that well-approximates skilled human performance. We optimized muscle volume by allowing the …

Neurogenesis-Mediated Forgetting Minimizes Proactive Interference., Jonathan R Epp, Rudy Silva Mera, Stefan Köhler, Sheena A Josselyn, Paul W Frankland

Brain and Mind Institute Researchers' Publications

Established memories may interfere with the encoding of new memories, particularly when existing and new memories overlap in content. By manipulating levels of hippocampal neurogenesis, here we show that neurogenesis regulates this form of proactive interference. Increasing hippocampal neurogenesis weakens existing memories and, in doing so, facilitates the encoding of new, conflicting (but not non-conflicting) information in mice. Conversely, decreasing neurogenesis stabilizes existing memories, and impedes the encoding of new, conflicting information. These results suggest that reduced proactive interference is an adaptive benefit of neurogenesis-induced forgetting.

Antenatal Depressive Symptoms And Antidepressant Use In Pregnancy, Jerry Yu-Hsiang Chen

Electronic Thesis and Dissertation Repository

Review of the current literature reveals inconsistent findings on potential associations between antidepressant use during pregnancy and adverse fetal and child health and development. This study aims to examine the effect of antenatal SSRI exposure on several neonatal (preterm birth, small- and large-for-gestational age, Apgar score, and neonatal intensive care unit admission) and child developmental outcomes (measured by Ages and Stages Questionnaire) while controlling for confounding by indication. Data were obtained from the Prenatal Health Project, a longitudinal cohort study of 2,357 women in London, Ontario. Results from univariable analysis discovered that infants exposed to in utero SSRIs were more …

Domestic Homicide And Homicide-Suicide In The Older Population, Brianna L. O'Neil

Electronic Thesis and Dissertation Repository

Extensive research has been conducted on domestic homicide in younger populations; however, very little is known about such incidents in the older population. It is vital that this gap in the literature be filled as Canada’s older population has been increasing. Data for this study was provided by the Ontario Domestic Violence Death Review Committee. Ninety-two domestic homicide and suicide cases were examined to determine whether there were differences between younger age groups (30 to 50 years of age) and older age groups (55 years of age and older). Information was gathered on prominent characteristics and risk factors within cases …

An Evaluation Of The Determinants Of Job Satisfaction In Canadian Family Physicians, Jana L. Malhotra

Electronic Thesis and Dissertation Repository

Physicians as a group appear to be satisfied with their work. However, there are some gaps in our current understanding of the determinants that impact the job satisfaction of Canadian family physicians. This thesis examined determinants of family physician job satisfaction using in-depth interviews with family physicians to achieve a broad perspective on their job satisfaction. This was complemented by a multivariate analysis that examined the professional and work-life balance satisfaction of physicians across this country. The findings from this research confirm the significance of a number of factors to the professional and work-life balance satisfaction of family physicians. Novel …

Muscle Strength Differences In Healthy Young Adults With And Without Generalized Joint Hypermobility: A Cross-Sectional Study, Pranay Jindal, Amitesh Narayan, Sailakshami Ganesan, Joy C. Macdermid

Bone and Joint Institute

© 2016 Jindal et al. Background: Generalized joint hypermobility (GJH), in the absence of symptoms, is a common clinical finding. The joint instability present due to excessive musculoskeletal flexibility in hypermobile joints impairs the external force production during muscle contraction. However, whether GJH is associated with muscle weakness is unclear. This study evaluated differences in upper and lower limb muscle strengths among asymptomatic young adults with and without GJH. Methods: One hundred six young adults (53 hypermobile, i.e. 25 male (mean age 22 ± 1.8); 28 female (mean age 21 ± 1.8), and 53 non-hypermobile, i.e. 25 male (mean age …

Testing The Interpersonal Theory Of Suicide In Community - Residing Older Adults, Dorian Murariu

Electronic Thesis and Dissertation Repository

Suicide rates among older adults are high in Canada and around the world. Evidence-informed and theory-driven research on late life suicide may help to devise effective interventions to reduce suicide rates among older adults. In this thesis, I tested the Interpersonal Theory of Suicide (IPTS: Joiner, 2005; Van Orden et al, 2010) using data collected from a community-based sample of older adults recruited for a larger study designed to assess risk and resiliency factors for late life suicide (Dr. Marnin Heisel, PI). According to the IPTS, (Hypothesis 1) the interpersonal constructs of perceived burdensomeness (PB) and thwarted belongingness (TB) can …

The Influence Of Areas Of Worklife And Compassion Satisfaction On Burnout Of Mental Health Nurses, Michelle Corinne Fredette-Carragher

Electronic Thesis and Dissertation Repository

The prevalence of burnout among nurses is linked to sub-optimal wellbeing and is reflected in higher than average rates of illness and absenteeism (Canadian Institute for Health Information, [CIHI], 2007). Additionally, there are consequences for clients including increased staff related errors and poor patient satisfaction. An improved person-job match in the six areas of worklife and higher compassion satisfaction may result in a workforce that is more engaged and able to achieve positive client outcomes. This study explores the relationship between person-job match and both compassion satisfaction and the emotional exhaustion component of burnout of mental health nurses through a …

Gene Expression Microarray Data From Human Microvascular Endothelial Cells Supplemented With A Low Concentration Of Niacin, Nica M. Borradaile, Jennifer M. Hughes-Large

Physiology and Pharmacology Publications

The systemic lipid modifying drug, niacin, can directly improve human microvascular endothelial cell angiogenic function under lipotoxic conditions, possibly through activation of niacin receptors [1]. Here we provide accompanying data collected using Affymetrix GeneChip microarrays to identify changes in gene expression in human microvascular endothelial cells treated with 10 μM niacin. Statistical analyses of robust multi-array average (RMA) values revealed that only 16 genes exhibited greater than 1.3-fold differential expression. Of these 16, only 5 were identified protein coding genes, while 3 of the remaining 11 genes appeared to be small nuclear/nucleolar RNAs. Altered expression of EFCAB4B, …

The Impact Of Surgical Technique On Coronal Plane Motion In Total Knee Arthroplasty, Kevin I. Perry

Electronic Thesis and Dissertation Repository

There are two predominant techniques used by most surgeons to perform total knee arthroplasty: gap balancing and measured resection. The purpose of the current study was to observe if surgical technique has an effect on post-operative coronal plane balance throughout range of motion and to observe if surgical technique has an effect on tibial and femoral component migration. This was a randomized, prospective controlled trial. Twenty-three patients (24 knees) were enrolled: twelve knees in each group. All knees showed migration of their components from the initial RSA to their RSA at 6 months. Migration was similar for both groups, but …

Knowledge ‘Translation’ As Social Learning: Negotiating The Uptake Of Research-Based Knowledge In Practice, Katherine Salter, Anita Kothari

Health and Rehabilitation Sciences Publications

BACKGROUND: Knowledge translation and evidence-based practice have relied on research derived from clinical trials, which are considered to be methodologically rigorous. The result is practice recommendations based on a narrow view of evidence. We discuss how, within a practice environment, in fact individuals adopt and apply new evidence derived from multiple sources through ongoing, iterative learning cycles.

DISCUSSION: The discussion is presented in four sections. After elaborating on the multiple forms of evidence used in practice, in section 2 we argue that the practitioner derives contextualized knowledge through reflective practice. Then, in section 3, the focus shifts from the individual …

Cardiac Acetylcholine Inhibits Ventricular Remodeling And Dysfunction Under Pathologic Conditions, Ashbeel Roy, Mouhamed Dakroub, Geisa C.S.V. Tezini, Yin Liu, Silvia Guatimosim, Qingping Feng, Helio C. Salgado, Vania F. Prado, Marco A.M. Prado, Robert Gros

Paediatrics Publications

Autonomic dysfunction is a characteristic of cardiac disease and decreased vagal activity is observed in heart failure. Rodent cardiomyocytes produce de novo ACh, which is critical in maintaining cardiac homeostasis. We report that this nonneuronal cholinergic system is also found in human cardiomyocytes, which expressed choline acetyltransferase (ChAT) and the vesicular acetylcholine transporter (VAChT). Furthermore, VAChT expression was increased 3- and 1.5-fold at the mRNA and protein level, respectively, in ventricular tissue from patients with heart failure, suggesting increased ACh secretion in disease. Weusedmicewith geneticdeletionof cardiomyocytespecificVAChTor ChATandmice overexpressingVAChT to test the functional significance of cholinergic signaling. Mice deficient for VAChT …

Development And Initial Validation Of Novel Multi-Planar Neck Strength Assessment And Neuromuscular Training Protocols, Theo H. Versteegh

Electronic Thesis and Dissertation Repository

Concussions are a serious health concern in today’s active society. There are many contributing factors to concussions but one that is starting to draw significant attention is the potential role the neck muscles play in mitigating concussive forces. There is evidence that stronger neck muscles may decrease an individual’s concussion risk. In order to fully define this role, an appropriate outcome measure for assessing neck strength is required. Once this is established, methods of training to improve neck strength can be evaluated for their effect on neck strength and subsequently effect on concussion risk. This thesis included three studies. Chapter …

Transitioning From Nursing Student To Clinical Teacher In Saudi Arabia, Aisha Namshan Aldawsari, Yolanda Babenko-Mould, Mary-Anne Andrusyszyn

Nursing Publications

Despite the remarkable growth in programs and educational facilities in Saudi Arabia (SA) since 1969 when nursing education was introduced, and the influx of government funding to advance nursing education, nursing is often not considered to be a desirable career option or a valued profession in SA. The main socio-cultural reasons contributing to this issue are that nurses traditionally work in mixed-gender environments for long hours and during night shifts, which would cause many female nurses to be away from their families. Thus, newly graduated nurses tend to be employed in roles that are highly respected by society, such as …

Sensory Plasticity In Human Motor Learning., David J Ostry, Paul L Gribble

Brain and Mind Institute Researchers' Publications

There is accumulating evidence from behavioral, neurophysiological, and neuroimaging studies that the acquisition of motor skills involves both perceptual and motor learning. Perceptual learning alters movements, motor learning, and motor networks of the brain. Motor learning changes perceptual function and the sensory circuits of the brain. Here, we review studies of both human limb movement and speech that indicate that plasticity in sensory and motor systems is reciprocally linked. Taken together, this points to an approach to motor learning in which perceptual learning and sensory plasticity have a fundamental role.

Planning Ahead: Object-Directed Sequential Actions Decoded From Human Frontoparietal And Occipitotemporal Networks., Jason P Gallivan, Ingrid S Johnsrude, J Randall Flanagan

Brain and Mind Institute Researchers' Publications

Object-manipulation tasks (e.g., drinking from a cup) typically involve sequencing together a series of distinct motor acts (e.g., reaching toward, grasping, lifting, and transporting the cup) in order to accomplish some overarching goal (e.g., quenching thirst). Although several studies in humans have investigated the neural mechanisms supporting the planning of visually guided movements directed toward objects (such as reaching or pointing), only a handful have examined how manipulatory sequences of actions-those that occur after an object has been grasped-are planned and represented in the brain. Here, using event-related functional MRI and pattern decoding methods, we investigated the neural basis of …

This Is What Copd Looks Like, Khadija Sheikh, Harvey O Coxson, Grace Parraga

Medical Biophysics Publications

Despite decades of research, and the growing healthcare and societal burden of chronic obstructive pulmonary disease (COPD), therapeutic COPD breakthroughs have not occurred. Sub-optimal COPD patient phenotyping, an incomplete understanding of COPD pathogenesis and a scarcity of sensitive tools that provide patient-relevant intermediate endpoints likely all play a role in the lack of new, efficacious COPD interventions. In other words, COPD patients are still diagnosed based on the presence of persistent airflow limitation measured using spirometry. Spirometry measurements reflect the global sum of all the different possible COPD pathologies and perhaps because of this, we lose sight of the different …